Spatial light modulators (SLMs) are devices used to control the distribution of light in an optical system. SLMs are typically configured as one or two-dimensional arrays of individually addressable optical elements, representing pixels of an image. These elements modify either the amplitude or the phase of the light distribution within the optical system.
SLMs can be divided into various types, including an electro-optic, magneto-optic, liquid crystal, and deformable mirror devices. These different types may be further characterized according to whether they are suitable for amplitude or phase modulation or both.
SLMs and their applications are described in the patents and patent applications listed in the "Related Patents" section above. Many applications involve using SLMs in display systems, where a SLM optics unit replaces a raster scan unit. These are "image generation" systems, in which the SLM receives data in the form of electrical signals for the purpose of determining how light is to be reflected by its pixel elements to a display screen, printer, or other such equipment. Thus, SLMs are traditionally used to transform an electrical signal to light patterns, and thereby generate an image.
Conventional means for capturing an image as an electronic signal, as opposed to recreating an image from a signal, do not involve the use of SLMs. In many applications the light receiving device is a photosensor array, in which an array of photosensor elements is used to differentiate pixels of the image. Each element of the array generates a signal corresponding to a pixel point of the image. This signal can be easily transmitted, digitized, or otherwise processed for reconstitution into an image at a desired time and place. A problem with such systems is that the sensor arrays are relatively expensive. A need exists for an image capture system that provides a less expensive alternative to photosensor-based systems.